Since a digital signal processor (DSP) has a multiplier accumulator, filter processing, frequency conversion, and matrix operation can be easily performed by software. To process image signals, however, there are too many picture elements to be processed. For example, in the case of digital TV signal processing, it is necessary to process signals at a rate of 20M picture elements per second. Therefore, because the required high-speed processing rate cannot be achieved only by the software processing using the DSP, it is necessary to use an exclusive circuit in addition to the DSP. To reduce the circuit scale, as described in "A Video Digital Signal Processor with a Vector-Pipeline Architecture, 1992 IEEE International Solid-State Circuits Conference DIGEST OF TECHNICAL PAPERS, pp. 72-73 (1992.2) by TOYOKURA, et. al." exclusive circuits are built in the DSP. The configuration of the DSP disclosed in the above document will be briefly described below referring to FIG. 1.